Considerable interest has been shown in recent years in the use of prostaglandin (PG) precursors in medicine.
For various reasons it is not practical to administer naturally-occurring prostaglandins such as PGE 1 and PGE 2 to patients. Consequently, considerable attention has focussed on the use of prostaglandin precursors including linoleic acid (9,12octadecadienoic acid), .gamma.-linolenic acid (6, 9, 12-octadecatrienoic acid) and dihomo-.gamma.-linolenic acid (5, 8, 11-eicosatrienoic acid), conversion in the body being believed to be as follows: ##STR1##